Yelloweye rockfish that has died of barotrauma. Reduced water pressure causes the air in the swim bladder to expand and push out the stomach and eyes. Photo: Hildering. Click to enlarge.

Here’s another case of a photo being worth a thousand words.

It is of a yelloweye rockfish that has died from barotrauma aka “pressure shock”.

Many rockfish species are particularly sensitive to reductions in pressure since the air in their swim bladders expands substantially. The swim bladder is a buoyancy control organ and even when slowly reeled in from a depth of only 20 m (60’), a rockfish’s swim bladder can expand to three times its size, putting pressure on the fish’s organs.

As is the case with the yelloweye rockfish in the photo, the swim bladder can expand to the point of causing the fish’s eyes to bulge out of their sockets and its stomach to be pushed out of its mouth.

Other than this being a sight that may not enhance your appetite for your rockfish catch, the death of rockfish due to barotrauma wouldn’t be a problem were it not that there are grave conservation concerns for many rockfish species.

Colossal management errors were made with overfishing slow-growing rockfish. Many species are extremely long-lived, slow to sexually mature, and the big old females are the most fertile – producing the most eggs and hatching the largest number of healthy young.

For example, yelloweye rockfish are believed to have a lifespan of up to 118 years, don’t reproduce until they are at least 12 years old, and the old females can incubate up to 2.7 million eggs!

This means that species are very slow to reproduce whereby, if you catch lots, especially the big females, you can devastate populations very quickly.

Another nail in the coffin of rockfish is that many adults also have high site fidelity so that by fishing one area, you can wipe out a community of fish.

Therefore, there are relatively strict limits on fishing for some rockfish species but of course you see dilemma. You may not be allowed to keep a rockfish but what if you reel one in, or if they are bycatch in a fishery, and their eyes and stomach are distended due to barotrauma?

There are studies that prove that if you were to quickly recompress the fish, it would stand a very good chance of survival, even where it appears dead at the surface (see video below). The fish could be brought back to depth with barbless weighted hooks, commercial “fish descenders”, or even by inverting a weighted milk crate over the fish. 

How wonderful it would be if more people would undertake the effort to recompress the fish, knowing how dire the situation is for many rockfish species. Imagine the further positive impact if people would choose to return the depleted species to depth even when they haven’t reached their catch limit, especially the big, highly productive females.

But, even if there was to be such enlightenment, many rockfish populations are so depleted that they need far more protection.

This is why there are Rockfish Conservation Areas (RCAs). These should be areas known to be the territory of depleted rockfish populations. As these are no-fishing zones, there is no chance of barotrauma and the rockfish populations that live in the area are given the time to rebuild to have more sexually mature fish and more big old super mamas.

Long live rockfish!

For how to save a life – a rockfish life – see this entertaining video by fish guru Milton Love with a rap song by Ray Troll.

Links:

Fantastic video showing how rockfish that appear dead at the surface due to barotrauma fully can revive at depth! From the Coastside Fishing Club.

Video showing how well a “fish descender” works to save rockfish that have suffered barotrauma.